PURPOSE: To make an extruder with a small diameter die possible to extrude a shape with a wide breadth, by extruding a shape in a crooked posture with a wide breadth, and by stretching this shape at its crooking point curved with a small curvature into a straight posture so as to obtain a shape in a normal posture in wide breadth.

CONSTITUTION: A shape 13a in a wide breadth is pushed by an extrusion mechanism 17 and is extruded through a die 16 of an extruder 15; hereupon, the shape 13a is extruded in a crooked posture bent at a crooking point 14 curved with a small curvature. When this extruded shape 13a is used, it is stretched by reversely bending at the crooking point 14, and a straight normal shape with a wide breadth is obtained.